The Mauthner-initiated startle response in teleost fish

1977 ◽  
Vol 66 (1) ◽  
pp. 65-81 ◽  
Author(s):  
R. C. Eaton ◽  
R. A. Bombardieri ◽  
D. L. Meyer
Keyword(s):  
Startle Response ◽  
High Speed ◽  
Visual Stimulation ◽  
Initial Position ◽  
Direct Result ◽  
Second Phase ◽  
Mauthner Cell ◽  
Spinal Motor ◽  
High Speed Cinematography ◽  
Characteristic Behaviour

1. A characteristic behaviour, the ‘Mauthner-initiated startle response’, was recorded and quantitatively analysed with high-speed cinematography (200 frames/sec) after vibrational stimulation in 11 of 13 teleost species which possess Mauthner cells. 2. The latency of the response is 5–10 msec. This behaviour has: (a) an initial phase, the ‘fast-body-bend’, lasting about 20 msec and consisting of a stereotyped displacement of the head and tail to one side and (b), a second phase, the ‘return-flip’, consisting of a non-stereotyped flip of the tail to the opposite side. 3. Within 100 msec after the start of the Mauthner-initiated startle response, most fish were displaced 0-5-1-5 body lengths from their initial position. The variability of the animal's location after 100 msec suggests that the behaviour is adaptively non-predictable; 4. In goldfish, the Mauthner-initiated startle response could also be elicited by visual stimulation. 5. We conclude that the fast-body-bend is the direct result of activation of one Mauthner cell and its spinal motor neurone pool. 6. In four species we described examples of apparently non-Mauthner initiated startle responses.

The Postdispersion Coalescence Phenomenon in Polymer-Polymer Blends

1984 ◽  
Vol 57 (2) ◽  
pp. 291-306 ◽  
Author(s):  
B. Z. Jang ◽  
D. R. Uhlmann ◽  
J. B. Vander Sande
Keyword(s):  
Phase Separation ◽  
Polymer Blends ◽  
High Speed ◽  
Volume Fraction ◽  
Interfacial Area ◽  
Substantial Effect ◽  
Second Phase ◽  
Interparticle Contact ◽  
Transmission Electron ◽  
High Speed Cinematography

Abstract Three novel experimental techniques have been developed to study the phase separation dynamics and morphology of polymer-polymer blends. Samples prepared from different materials by different methods appear to follow the same phase transformation behavior. The minor phase, dispersed as discrete particles, may change its phase morphology by aggregation and coalescence. The aggregation process involves the change in either particle location (small particles may translate) or particle geometry (to reduce interfacial area). Once the interparticle contact is effected, the flattened interface will break and allow for sintering of particles. The particle size distribution is more or less random and tends to broaden with time. The volume fraction of the second phase has a substantial effect on its growth rate. It has been demonstrated that a combination of hot-staged optical microscopy, transmission electron microscopy, high-speed cinematography, and the three novel sample preparation techniques facilitate a detailed study on the late-stage mechanisms of phase separation of polymeric blends.

Aerodynamic and aeroacoustic performance investigations on modified H-rotor Darrieus wind turbine

2021 ◽  
pp. 0309524X2110039
Author(s):  
Amgad Dessoky ◽  
Thorsten Lutz ◽  
Ewald Krämer
Keyword(s):  
Wind Turbine ◽  
High Speed ◽  
Cfd Simulation ◽  
Vertical Axis ◽  
3D Models ◽  
Power Coefficient ◽  
Design Parameters ◽  
Second Phase ◽  
Vertical Axis Wind Turbine ◽  
Guide Vanes

The present paper investigates the aerodynamic and aeroacoustic characteristics of the H-rotor Darrieus vertical axis wind turbine (VAWT) combined with very promising energy conversion and steering technology; a fixed guide-vanes. The main scope of the current work is to enhance the aerodynamic performance and assess the noise production accomplished with such enhancement. The studies are carried out in two phases; the first phase is a parametric 2D CFD simulation employing the unsteady Reynolds-averaged Navier-Stokes (URANS) approach to optimize the design parameters of the guide-vanes. The second phase is a 3D CFD simulation of the full turbine using a higher-order numerical scheme and a hybrid RANS/LES (DDES) method. The guide-vanes show a superior power augmentation, about 42% increase in the power coefficient at λ = 2.75, with a slightly noisy operation and completely change the signal directivity. A remarkable difference in power coefficient is observed between 2D and 3D models at the high-speed ratios stems from the 3D effect. As a result, a 3D simulation of the capped Darrieus turbine is carried out, and then a noise assessment of such configuration is assessed. The results show a 20% increase in power coefficient by using the cap, without significant change in the noise signal.

New findings on life history traits of Xenos peckii (Strepsiptera: Xenidae)

2014 ◽  
Vol 146 (5) ◽  
pp. 514-527 ◽  
Author(s):  
M. Hrabar ◽  
A. Danci ◽  
S. McCann ◽  
P.W. Schaefer ◽  
G. Gries
Keyword(s):  
Life History ◽  
High Speed ◽  
Life History Traits ◽  
Suture Line ◽  
Paper Wasp ◽  
Anterior Portion ◽  
New Findings ◽  
High Speed Cinematography ◽  
Normal Speed ◽  
Wasp Nests

AbstractWe studied life history traits of Xenos peckii Kirby (Strepsiptera: Xenidae), a little-known parasite of the paper wasp Polistes fuscatus (Fabricus) (Hymenoptera: Vespidae) in North America. We field-collected 24 wasp nests in early July 2012, isolated parasitised wasps, tracked life history events of X. peckii, and recorded such behaviour as emergence of males and mating by normal-speed and high-speed cinematography. To emerge, males first cut the puparium with their mandibles along an ecdysial suture line, and then push aside the pupal cap during emergence. The endoparasitic females engage in active calling (pheromone release) behaviour by slowly inflating their cephalothorax, and then extruding it even farther out of, and tilting it away from, the host wasp abdomen. Seasonal and diel (afternoon) emergence periods of males coincide with seasonal and diel receptivity and calling periods of females. Males approach calling females in a swaying flight with smooth turns. They typically land on the anterior portion of the host wasp's abdomen, and then step backward until they make contact with the cephalothorax of the female. As soon as their mesothoracic legs contact the female's cephalothorax, they curl around it, and the male initiates mating. Thereafter, the female fully retreats and never re-mates.

Angular Momentum Requirements of the Twisting and Nontwisting Forward 1 1/2 Somersault Dive

1987 ◽  
Vol 3 (1) ◽  
pp. 47-62 ◽  
Author(s):  
Ross H. Sanders ◽  
Barry D. Wilson
Keyword(s):  
Angular Momentum ◽  
High Speed ◽  
Center Of Gravity ◽  
Transverse Axis ◽  
Free Position ◽  
High Speed Cinematography ◽  
The Difference ◽  
Hip Flexion ◽  
Commonwealth Games

This study investigated the in-flight rotation of elite 3m springboard divers by determining the angular momentum requirement about the transverse axis through the divers center of gravity (somersault axis) required to perform a forward 1 1/2 somersault with and without twist. Three elite male divers competing in the 1982 Commonwealth Games were filmed using high-speed cinematography while performing the forward 1 1/2 somersault in the pike position and the forward 1 1/2 somersault with one twist in a free position. The film was digitized to provide a kinematic description of each dive. An inclined axis technique appeared to be the predominant means of producing twist after takeoff from the board. The angular momentum about the somersault axis after takeoff was greater for the forward 1 1/2 somersault with twist than the forward 1 1/2 somersault without twist for all three divers. The difference in angular momentum between the two dives of each diver ranged from 6% to 19%. The most observable difference between the dives during the preflight phases was the degree of hip flexion at takeoff. There was more hip flexion at takeoff in 5132D than 103B for all three divers. This difference ranged from 9° to 18° (mean = 14°).

Kinematics of Tongue Projection in Chamaeleo Oustaleti

1991 ◽  
Vol 159 (1) ◽  
pp. 109-133 ◽  
Author(s):  
PETER C. WAINWRIGHT ◽  
DAVID M. KRAKLAU ◽  
ALBERT F. BENNETT
Keyword(s):  
High Speed ◽  
Prey Capture ◽  
Maximum Velocity ◽  
Head Movements ◽  
Florida State University ◽  
State University ◽  
Maximum Acceleration ◽  
Related Family ◽  
High Speed Cinematography ◽  
Tongue Movements

The kinematics of prey capture by the chamaeleonid lizard Chamaeleo oustaleti were studied using high-speed cinematography. Three feeding sequences from each of two individuals were analyzed for strike distances of 20 and 35 cm, at 30°C. Ten distances and angles were measured from sequential frames beginning approximately 0.5 s prior to tongue projection and continuing for about 1.0 s. Sixteen additional variables, documenting maximum excursions and the timing of events, were calculated from the kinematic profiles. Quantified descriptions of head, hyoid and tongue movements are presented. Previously unrecognized rapid protraction of the hyobranchial skeleton simultaneously with the onset of tongue projection was documented and it is proposed that this assists the accelerator muscle in powering tongue projection. Acceleration of the tongue occurred in about 20ms, reaching a maximum acceleration of 486 m s−2 and maximum velocity of 5.8m s−1 in 35 cm strikes. Deceleration of the tongue usually began within 5 ms before prey contract and the direction of tongue movement was reversed within 10 ms of prey contact. Retraction of the tongue, caused by shortening of the retractor muscles, reached a maximum velocity of 2.99 ms−1 and was complete 330 ms after prey contact. Projection distance influences many aspects of prey capture kinematics, particularly projection time, tongue retraction time and the extent of gape and head movements during tongue retraction, all of which are smaller in shorter feedings. Though several features of the chameleon strike have apparently been retained from lizards not capable of ballistic tongue projection, key differences are documented. Unlike members of a related family, the Agamidae, C. oustaleti uses no body lunge during prey capture, exhibits gape reduction during tongue projection and strongly depresses the head and jaws during tongue retraction. Note: Present address: Department of Biological Sciences, Florida State University, Tallahassee, FL 32306, USA.

Kinematic analysis of tongue movements during chemosensory behaviour in the European green lizard, Lacerta viridis (Reptilia: Lacertidae)

1992 ◽  
Vol 70 (10) ◽  
pp. 1886-1896 ◽  
Author(s):  
Véronique Goosse ◽  
Vincent L. Bels
Keyword(s):  
High Speed ◽  
Prey Capture ◽  
Principal Component ◽  
Upward Movement ◽  
High Speed Cinematography ◽  
Tongue Movements ◽  
Lacerta Viridis ◽  
Tongue Flicking ◽  
Stationary Interval ◽  
Tongue Displacement

High-speed cinematography (100 frames/s) was used to allow quantitative analysis of the kinematic profiles of tongue and jaw displacements during chemosensory activities in the scleroglossan lizard Lacerta viridis. The types of tongue flicking were simple downward extensions (SDE), single oscillations (SOC), and submultiple oscillations (SMOC) of the tongue out of the mouth. The SMOC type involves a downward or upward movement of the tongue performed before a typical oscillation and it is therefore suggested that this is an intermediate category of flick between the typical SOC and MOC of lizards. Closing and opening of the mouth in SDE, SOC, and SMOC cycles may or may not be separated by a stationary stage during which the jaws are held open at a constant gape. The duration of this stationary interval increases from SDE to SMOC. Gape cycles do not show any division into slow and fast stages. The gape is produced largely by depression of the lower jaw; the upper jaw is slightly elevated by protrusion of the tongue. Patterns of correlation of kinematic variables depicting jaw and tongue movements differed between SDE, SOC, and SMOC. A principal component analysis shows that the three flick types overlap in a multivariate space constructed from the kinematic variables depicting jaw and tongue displacements. Overlap between SOC and SMOC categories is greater than that between SOC, SMOC, and SDE categories. The kinematic patterns of tongue displacement during SMOC in Lacerta viridis show similarities with those of MOC in other lizards and in snakes. Kinematically, the pattern of jaw and tongue displacements of Lacerta viridis during chemosensory activities shows similarities with those that occur during drinking and prey capture.

scholarly journals THE MECHANISM OF THE NEPHRIDIAL APPARATUS OF PARAMECIUM MUL TIMICRONUCLEATUM

1968 ◽  
Vol 37 (1) ◽  
pp. 139-146 ◽  
Author(s):  
Alan E. Organ ◽  
Eugene C. Bovee ◽  
Theodore L. Jahn ◽  
Duncan Wigg ◽  
James R. Fonseca
Keyword(s):  
Electron Microscopy ◽  
Excretory Pore ◽  
High Speed ◽  
Cell Membranes ◽  
Recent Analysis ◽  
Opposite Wall ◽  
Active Contraction ◽  
High Speed Cinematography ◽  
Excretory Canal

Recent analysis of the mechanism of the nephridial apparatus of Paramecium multimicronucleatum by high-speed cinematography (300 fps at x 250) confirms the observations by electron microscopy (Schneider, 1960) that once the pore is opened, the vesicle is invaginated by adjacent cytoplasm and is emptied by collapsing under pressure from that cytoplasm, aided perhaps by pressure of the fibrils which anchor the ampullae to the excretory canal. There is no indication of active contraction of the vesicle or its membrane. There is no permanent pore to the vesicle. The vesicle is closed by a sealing of the ruptured membrane where it is in contact with the pellicular excretory canal. At onset of expulsion of vesicular fluid the membrane across the basal opening of the excretory canal is ripped along one semicircular portion of the excretory pore and is driven up against the opposite wall as a flap while the water rushes out. A constriction of the vesicular and cell membranes at the base of the excretory canal reseals the opening.

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